Plotting instrument



July 10, 1945.

T. P. FLYNN ET AL- PLOTTING INSTRUMENT Filed March 10, 1945 m mw 4 Sheets-Sheet l INVENTORS A.J.KRAMER T. P. FLYNN AT'roR EYS July 10, 1945.

"r. P. FLYNN EI'AL 2,380,103

PLOTTING INSTRUMENT Filed March 10, 1943 4 Sheets-Sheet 2 INVENTORS A.J. KRAMER IT. P. FLYNN W ATT NEYS July 10, 1945.

T. P. FLYNN ET AL 0,103

PLOTTING INSTRUMENT Filed March 10, 1945 4 Sheets-Sheet 5 INVENTORS A J. KRAMER T. P. FLYNN BY ATTO NEYS I T. P. FLYNN ET AL PLOTTING INSTRUMENT 4 Sheets-Sheet 4 Filed March 10, 1943 July 10, 1945.

INVENTORS A .J KRAM ER T. P. FLYN N ATTORNEYS Patented July 10, 1945 J, Kramer, Arlington, Va., assi'gnors to Claude It. Wickard, as Secretary of Agriculture of the United States of in office America, and his successors Application March 10, 1943, Serial No. 478,644

" Claims. ('01. 33-20) (Granted under the act amended April 30, 1928; 370 0. G. 757) This application is made under the act of March 3, 1383, as amended by the act of April 30, 1928, and the invention herein described, if patented,

1 may be manufactured and used by or for the Government of the United-States of America for governmental purposes without the payment to us of any royalty thereon.

This invention relates to a plotting instrument of the same general character as that disclosed in the patent to Wernstedt, No. 2,303,099, granted November 24, 1942, and has among its objects improvements" in such an instrument, particularly relative to improvement of the means for carrying the index marks and tracing point, the simplification of certain details of structure of the means for counter-balancing the bar carrying the index marksyand the provision of means for holding th tracing paperin position on the map table, and such other objects as will be apparent ifrom'the following specification and annexed drawings. V

In the patent to which reference is made above, the carriage for the index mark and tracing point is supported on feet slidably resting on plane surfaces, and is constrained in its movement; by i a parallelism mechanism comprising essentially a pair of drafting machines suitably connecting the carriage and frame of the instrument. Such mechanism is awkward and not easily handled:

whereas in the corresponding mechanism of this invention the Carriage'and its linkage are supported solely by the frame, resulting in a simpier, sturdier and more easily manipulated instrument. Simplification is also effected ,in this invention by forming the vertical columns of the carriage as tubes and suspending the counterweightswithin them, rather than by providing additional tubes for this purpose, and, as an added feature, provision is made in a simple manner for holding the tracing paper in position on the map table.

Referring to the drawings,

Figure 1 is a front elevation of the plotting instrument;

Figure 2 is a side elevation thereof;

Figure 3 is a section on theline 3--3 of Figure 2; i

Figure 4 is a fragmentary, three-dimensional view of the linkage for carrying the index marks d tr poi t; i

Figure 5 is a section on the line 55 of Figure 4; and i r Figure 6 is a fragmentary section on the line 6-6 f i u e i 7 Referring to the drawings in particular, the

of March 3, 1883 as embodiment illustrated is provided with a base I l, suitably supported on adjustable leveling rests l2 located'at eachcorner of the base. Frame members l3 and t4 shaped to provide uprights l5 and I6 and horizontal arms I! and I8, respectively, are suitablysecured to the rear corners of the base with the horizontal arms extending forwardly .thereabove. Transverse parallel front and rear barsl9 and extend across thefor- Ward ends of the horizontal arms and are secured thereto by set screws 2| in the manner illusf trated.

A unit 22, forming part of a stereoscope and having eyepieces 23 and 24 and eye mirrors 25 and 26, is carriedby bracket 21 which, in turn,

is carried ,on another bracket 28. The latter bracket is adjustably mounted on the front bar I9 with a tight sliding fit, and has a rearwardly extending projection 29 positionedbeneaththe rear bar 20. A wing screw 30, threaded through" the projection 29 and engaging thebar 20,provides for adjustingthe position of the unit 22 ver- .tically. The unit 22 is adjustable on horizontal pivot bolt 3! by manipulation of screws 32 and 33, which arethreaded through projections on bracket'Zl and bear on an abutment fixed to the stereoscope uni-t 22, and is adjustable on vertlcal pivot bolt 35 by manipulation of similar screws, one of which is shown at 36, whichare threaded through other projections on bracket 21 and bear on a stationary abutment 31 fixedlto the bracket 28.

Sterescope wing mirrors 38 and 39 are carried which reference is made to the paragraph above.

Phototables 42 and 43 for supporting the stereoscopic pictures are suitably mounted on the base I l at the front side. The manner of supporting and adjusting the tables is substantially the same as that described in the above-mentioned patent,

to which reference is made for a complete description thereof. A map table 44 is also mou f ied on the base II, and a holder 45 is provided tor holding a rolled strip of tracing paper 46 on which maps are drawn. The holder 45. may be fabricated from a suitable strip of material formed to provide upwardly facing troughs 41 and-l8 positionedbeneath the map table in which the rolled ends of a tracing paper are carried.

The section of the holder between the troughs is secured to the base ll beneath the map table 44. A section of the tracing paper 46 on the" table 44 is held taut by the weight of the rolled ends, which may be additionally weighted, if necessary, by rolling the ends of the paper 46 on heavy bars 49 and 50.

Frames 5| and 52, carrying index mark disks with the index marks movable in three coordinate directions in the field of vision of the stereoscope, are mounted on horizontal bar 53, which in turn is mounted for vertical movement on racked vertical columns in the form of tubes 54 and 55, and is operated by a hand wheel 56 driving a shaft 51 to which pinions, one of which is shown at 58, are attached and meshed with the racked tubes. A graduated scale wheel 59 is movable with the hand wheel, and its setting is indicated by index pointer 68. i

The bar 53 and parts carried with it are counter-balanced by weights one of which is shown at 6| disposed inside the vertical tubes/54 and 55, respectively. The counterweights are suitably connected to the bar by flexible cables 62 and 63, which are attached at their free ends to the counter-balanced parts, and are belted over pulleys '64 and 65 attached at the top of the tubes to brackets 89 and 98. Obviously only one of the columns may be a tube and only one weight be used. The flexible cable 83 may, for example, be extended across and over another pulley on bracket 89 and connected to weight 6|.

1 One frame 5| is made readily adjustable to the other. Frame 5|, for example, is adjustable vertically and horizontally by manipulation of screws 66 and 91 journaled in a bracket 68, which is slidable on bar 53, and is threaded through the frame. Screw 61 is journaled in a bracket 69, which is fixed on bar 53 and is threaded through bracket 68. The frame 5| is guided in its vertical movement by guides 10 secured to bracket 68 and slidably fitted in apertures extending through the frame.

Tracing .point H is clamped in the bracket 12 by thumb screw 13. The bracket 12 is secured to a horizontal rod 14 by means of a clamp plate 15 and the rod is fixedly attached at its ends to tubes 54 and 55. The tracing point is spring-pressed downwardly and may be raised by anupward lift and rotation of thumb grip 16.

The parts heretofore described, although improved -in structure, are substantially the same in their general function as the corresponding parts of the patent to which reference is made above.

The principal improvement in the present invention over the patent relates to the means for movably supporting the parts carrying the index marks and tracing point. This means, as shown most clearly in Figure 3, comprises a linkage of rigid members, or sides, forming at least two parallelograms with a common side, with the side of the first parallelogram opposite the common side fixed against movement, and with all corners hinged, allowing freedom of movement in all horizontal directions of the unfixed side of the second parallelogram which is opposite the common side and which forms a carriage for the index marks and tracing point.

The structure of the linkage is clearly illustrated and need not be described relative to minor details.

The first parallelogram has as its fixed side thebase II to which the uprights l5 and 16 are fixedly secured. Sides 88 and 8|, which are of equal length, are hinged at their ends to the uprights on pintle pins 82 and 83, respectively, and at their opposite ends to the ends of the common side 84, which is of length equal to the distance between the hinges on the uprights, on pintle pins and 86. The second parallelogram has itssides 81 and 88, which are of equal length, hinged at their ends on pintle pins 85 and 86, and at their opposite ends on the movable side, or carriage, which is also of length equal to the distance between the hinges on the uprights and which comprises horizontal bar 53, rod 14 and tubes 54 and 55. The tubes are journaled at their ends in brackets 89, 90, 9| and 92, attached to the ends of the sides 8! and 88. For ease in movement, the pintle pins may be fixed in reference to one of the sides and frictionless bearings (not shown) provided at the bearing points.

In order to provide for precise adjustment of the linkage, the upper ends of the hinges connected on the uprights l5 and is are made adjustable upwardly and laterally relative to their points of attachment. This is accomplished by having brackets 93 and 94 movably mounted on the uprights. In reference to upright 16, for example, bracket 94 is provided with enlarged apertures for receiving the attaching stud bolts 95 and 95, and set screws 91 and 93 are threaded through lugs 99 and I 08 integral with the uprights and into abutment with the sides of the bracket. The lower bracket IOI may be mounted for slight movement by having its apertures enlarged for receiving the attaching stud bolts I02 and I03.

From the structure disclosed, it will be observed that the index marks and tracing point are carried by the movable side of the linkage and will always remain in the same position relative to each other, except for abutments and vertical displacements; that the linkage is supported solely by the frame and the index marks are constrained to move in traversing the stereoscopic pictures so that every position of the marks is parallel to every other position; and that the tracing point will trace a figure similar to any figure traversed by the index marks.

Having thus described the invention, what is claimed is:

1. In a plotting instrument of the character described, a stereoscope, and index marks movable in the field of vision of the stereoscope, said index marks being carried by a carriage comprising vertical columns at least one of which is a tube, a, horizontal bar on which the index marks are supported and which is slidably mounted on the vertical columns, and at least one counterweight suitably connected to the bar for counterbalancing the weight of the bar and its carried parts and disposed inside the vertical tube.

2. In a plotting instrument of the character described, a stereoscope and index marks movable in three coordinate directions in the field of vision of the stereoscope, said index marks being carried by a carriage comprising a, pair of vertical tubes, a bar on which the index marks are supported and which is slidably mounted on the vertical tubes, and a pair of counterweights, each suitably connected to the bar for counter-balancing the weight of the bar and its carried parts and disposed one inside each vertical tube.

3. In a plotting instrument of the character described, a frame; a stereoscope supported by the frame; a mechanism comprising a linkage of rigid members forming at least two parallelograms with all corners hinged, with a common side, and'with the side of the first parallelogram opposite the common side fixed against movement in reference to the frame, said linkage begrams with all corners hinged, with a common side and with the side of the first parallelogram opposite the common side fixed against movement in reference to the frame, said linkage being supported solely by said fixed side, the side of the last parallelogram opposite a common side forming a carriage having vertical columns, a bar mounted for vertical sliding movement on the columns, and a rod fixedly attached to the 5. In a plotting instrument of the character described, a rigid frame; a stereoscope supportvertical columns; index marks carried by the 2 bar in the field of vision of the stereoscope; and a tracing point secured to the rod.

ed by the frame; tables for supporting stereoscopic pictures below the stereoscope; three members hinged together in series at points and hinged to said frame forming therewith a parallelogram linkage; parallel members hinged to said linkage at points remote from the frame and extending outwardly from the, linkage; a carriage hinged to said parallel members, said carriage comprising vertical columns, a bar slidable on said columns between the stereoscope and tables, and means for raising and lowering said bar; and index marks carried by said bar, said members being sufliciently rigid and so connected at the hinge points to support the weight of the carriage free of any other support.

THEODORE P. FLYNN. ALBERT J. KRAMER. 

